臺灣博碩士論文加值系統

摘要
本論文可分為三大部分。第一部分為運用不同的操作條件去做暫態CO毒化實驗。暫態實驗中操作條件分別為固定電池電位(0.5、0.6、0.7 )與固定電池電流(600、1000、1200 )，CO濃度為52.7ppm。由實驗結果可知，不論定何種電位執行暫態實驗所得到的穩態毒化性能都是一樣的。但發現如果固定越高的電流去做毒化實驗，電池的CO容忍度能夠被提升，相對地有較佳的電池性能。第二部分為討論空氣吹離法與其注入時機對燃料電池CO容忍度的影響。在暫態毒化實驗中空氣注入時間分別為三分鐘與三十分鐘。結果可知不論空氣何時注入都能有效提升電池的CO容忍度，使性能回復。但空氣越早注入越能更有效降低CO毒化效應，而所需的空氣量也會因此減少。第三部分為比較不同陽極觸媒(Pt alloy and Pt)對CO容忍度之差異。當沒有配合使用空氣吹離法時，使用Pt alloy陽極觸媒可以較有效地降低毒化效應，可得到較高的電池性能。但運用空氣吹離法後，發現陽極觸媒成分對CO容忍度的影響變的不明顯。那是因為不論何種觸媒(Pt alloy and Pt)空氣吹離法都能大幅提升電池對抗CO毒化的能力。

ABSTRACT
This thesis consists of three parts. The first one carries out the transient CO (52.7ppm) poisoning test with fixed cell voltage (0.5, 0.6 and 0.7V) and current density conditions (600, 1000 and 1200 ), respectively. For the fixed cell voltage case, the results of transient CO poisoning test indicate that varying cell voltage does not change the stable poisoned polarization behaviors. For the fixed current density one, the higher current density can improve CO tolerance. The second one investigates the effects of air-bleeding with different introduced timing (3 and 30min) in the transient poisoning CO tests (10.1, 25 and 52.7ppm). With air-bleeding, it is able to improve the fuel cell CO tolerance and recover the poisoned performance no matter what the air introducing timing. With an earlier introducing timing, 3min, it can obtain a better recovery performance and the optimum ratio of air-bleeding is lower. The third one studies the effect of using different anode catalyst component (Pt alloy and Pt) on the cell performance in CO poisoning tests. Without air-bleeding, Pt alloy anode catalyst has a better CO tolerance comparing to pure Pt anode catalyst. With air-bleeding, it can increase CO tolerance effectively no matter what kind anode catalyst (Pt or Pt alloy) is used.

CONTENTS

ABSTRACT (CHINESE)………………………………………………I

ABSTRACT (ENGLISH)…………………………………………………II

ACKNOWLEDGMEN……………………………………………………III

CONTENTS………………………………………………………IV
LIST OF TABLES……………………………………………………VI
LIST OF FIGURES……………………………………………………………VII
NOMENCLATURE…………………………………………………………..……X
CHAPTER 1 INTRODUCTION…………………………………………….…….1
1.1 Background…………………………………………………………...……...1
1.2 Literature Review…………………………………………………………….4
1.3 Scope of Present Study……………………………………………………...12
CHAPTER 2 EXPERIMENTAL APPARATUS………………………………....14
2.1 Fuel Cell Test Station………………………………………..………….…..14
2.1.1 Electronic Load…………………………………………...……….….14
2.1.2 MFC Readout Power Supply………………………...……………….15
2.1.3 Power Supply…………………………………...…………………….15
2.1.4 Gas Pipelines Controller………………………………………...……16
2.1.5 Liquid-Gas Separator……………………………………...………….16
2.2 Test Sample of PEMFC…………………………….……….……….……...17
2.3 Test conditions………………………………………………………………18
2.4 Procedure of the Experimental Operation……………………………..…....19
CHAPTER 3 UNCERTANINTY ANALYSIS…………………………….……..22
3.1 Analyses of the Propagation of Uncertainty in Calculations……………….22
3.2 The Analysis of CO Concentration……………………....………………....23
3.3 The Uncertainty of Test Station Apparatus…………………………...…….24
3.4 The Experimental Repeatability………………………………..…………...26
CHAPTER 4 RESULTS AND DISSCUSSION……………………………….…28
4.1 Poisoning Effects of Fixed Cell Voltage and Current Density.......................28
4.2 Effect of Air-Bleeding Timing………………………………………...…....34
4.2.1 Long Duration Poisoning (30min)………………………………........35
4.2.2 Short Duration Poisoning (3min)…………………………………......40
4.2.3 Effect of specific poisoning duration……………………………........42
4.3 Effect of Different Catalyst Components………………………………..….44
CHAPTER5 CONCLUSIONS…………………………………………………....50
REFERENCE…………………………………………………………….………..53
TABLES…………………………………………………………………………....56
FIGURES……………………………………………………………………..……68



LIST OF TABLES
Table 1.1 Summary of investigation of CO tolerance on PEM fuel cells.………….56
Table 1.1 Summary of investigation of CO tolerance on PEM fuel cells (continuity).…………………………………………………………..….57
Table 1.1 Summary of investigation of CO tolerance on PEM fuel cells (continuity).………………………………………………………….…..58
Table 2.1 Fuel cell operation conditions…………………………………………....59
Table 3.1 Uncertainty of electronic load potential meter…………………….…….60
Table 3.2 Uncertainty of electronic load current meter………………………….…60
Table 3.3 Uncertainty of anode MFC……………………………………………....61
Table 3.4 Uncertainty of cathode MFC…………………………………………….61
Table 3.5 Uncertainty of air-bleeding MFC……………………....………………..61
Table 3.6 Uncertainty of anode temperature controller………………………….…62
Table 3.7 Uncertainty of cathode temperature controller……………………….….62
Table 3.8 Uncertainty of cell temperature controller……………………………….62
Table 3.9 The table of experimental repeatability for baseline performance (case1)……………………………………………………………………63
Table 3.10 The table of experimental repeatability for baseline performance (case 2)…………................................................64
Table 3.11 The table of experimental repeatability for baseline performance (case 3, Pt anode catalyst)……………………........................................65
Table 4.1 Summary data from the transient CO poisoning experiments with two different specific times for 52.7ppmCO………………………………..66
Table 4.2 Summary data from the transient CO poisoning experiments
with two different specific times for 25ppmCO…………...…………….66
Table 4.3 Summary data from the transient CO poisoning experiments with two different specific times for 10.1ppmCO………………………………..67
Table 4.4 summary data from the transient CO poisoning experiments with two different anode catalysts for 52.7ppmCO………....................................67



LIST OF FIGURES
Fig. 1.1 Scheme diagram of the thesis……………………………………………...68
Fig. 2.1 Schematic drawing of overall experimental system……………………….69
Fig. 2.2 The HP 6060B electronic load…………………………………………….70
Fig. 2.3 The MFC readout power supply…………………………………………...70
Fig. 2.4 The power supply of the test station……………………………………….71
Fig. 2.5 The gas pipelines controller……………………………………………….71
Fig. 2.6 The fuel cell test station…………………………………………………....72
Fig. 2.7 The MEA, GDL, gasket…………………………………………………...73
Fig. 2.8 The flow channels………………………………………………………....73
Fig. 2.9 The current collector…………………………………………....................74
Fig. 2.10 The end plank……………………………………………………….……74
Fig. 2.11 All components of PEMFC………………………………………….…...75
Fig. 2.12 The sequence of fabricated fuel cell…………………………….………..75
Fig. 2.13 The test fuel cell………………………………………………………….76
Fig. 4.1 Transients poisoning and recovery performances with different poisoning conditions (0.5, 0.6 and 0.7V)…………………………………………...77
Fig. 4.2 The baseline polarization curve, the poisoned and recovered polarization curves with different poisoning conditions (0.5, 0.6 and 0.7V)…………78
Fig. 4.3 Transients poisoning and recovery performances with different poisoning conditions (600, 1000 and 1200 )…………………………...…...79

Fig. 4.4 The baseline polarization curve, the poisoned and recovered polarization curves with different poisoning conditions (600, 1000 and 1200 )
…………………………………………………………………………….80
Fig. 4.5 Anode potential due to CO (52.7ppm) poisoning with different transient poisoning conditions (0.5, 0.6 and 0.7V), (600, 1000 and 1200 ).81

Fig. 4.6 Transients poisoning and recovery performances with different CO concentrations (10.1, 25 and 52.7ppm) at 800 …………………..82

Fig. 4.7 The baseline polarization curve, the poisoned and recovered polarization curves with different CO concentrations (10.1, 25 and 52.7ppm)………...83
Fig. 4.8a Transient air-bleeding test with 52.7ppm CO at 800 , the cell potentials recover to 0.681, 0.684 and 0.687V as the air-bleeding ratios are 2, 3 and 4%, respectively……………………...........................................84
Fig. 4.8b Transient performance with continues changing air ratio and 52.7ppm CO………………………………………………………………………..85

Fig. 4.9 The baseline polarization curve, the poisoned polarization curve and recovered polarization curves as a function of air-bleeding ratio………....86
Fig. 4.10a Transient air-bleeding test with 25ppm CO at 800 , the cell potentials recover to 0.688 and 0.691V as the air-bleeding ratios are 2 and 3%, respectively……………………………………………………87
Fig. 4.10b Transient performance with continues changing air ratio and 25ppm CO……………………………………………………………………....88
Fig. 4.11 The baseline polarization curve, the poisoned polarization curve and recovered polarization curves as a function of air-bleeding ratio………..89
Fig. 4.12a Transient air-bleeding test with 10.1ppm CO at 800 , both 1.5 and 2% of air-bleeding ratios let cell potentials recover to 0.695V…....90
Fig. 4.12b Transient performance with continues changing air ratio and 10.1ppm CO………………………………………………………………………91
Fig. 4.13 The baseline polarization curve, the poisoned polarization curve and recovered polarization curves as a function of air-bleeding ratio……......92
Fig. 4.14 Summarizes the recovered steady-state polarization curves by air-bleeding with different CO poisoning concentrations (52.7, 25 and 10.1ppm)…...93
Fig. 4.15a, b and c Transient air-bleeding test with different CO poisoning concentrations (52.7, 25 and 10.1ppm), the timing of air-bleeding is 3min…………………………………………...94
Fig. 4.16 Summarizes the recovered steady-state polarization curves by air-bleeding with different CO poisoning concentrations (52.7, 25 and 10.1ppm), the timing of air-bleeding is 3min in transients tests…………………...……95
Fig. 4.17 The comparisons of recovered steady-state polarization curves with different air-bleeding timing (3 and 30min), with 52.7ppm CO……..….96
Fig. 4.18 The comparisons of recovered steady-state polarization curves with different air-bleeding timing (3 and 30min), with 25ppm CO…………..97
Fig. 4.19 The comparisons of recovered steady-state polarization curves with different air-bleeding timing (3 and 30min), with 10.1ppm CO…..…….98
Fig. 4.20 Transients poisoning and recovery performances with different anode catalyst (Pt alloy and Pt), with 800 and 52.7ppm CO………...99

Fig. 4.21 The baseline polarization curve, the poisoned and recovered polarization curves with different anode catalyst (Pt alloy and Pt)………………….100

Fig. 4.22 Transient air-bleeding test with 52.7ppm CO at 800 and Pt anode catalyst, the cell potentials recover to 0.605, 0.620, 0.637, 0.642 and 0.649V as the air-bleeding ratios are 2, 3, 4, 5, 6 and 7%, respectively……………………………………………….………….…101
Fig. 4.23 Summarizes the recovered steady-state polarization curves as a function of air-bleeding ratio with different anode catalyst (Pt and Pt alloy), with 52.7ppm CO…………………………………………………………….102


NOMENCLATURE
I Current (A) produced from fuel cell
i Current density ( )

OCV Open circuit voltage (V)
V Cell voltage (V)

Anode potential (V)
T Temperature (℃)
t Time (sec)
C CO concentration (ppm)

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